Attenuating circuit for electric organ



Nov. 24, 1959 D. BONHAM 2,913,948

ATTENUATING CIRCUIT FOR ELECTRIC ORGAN Filed Jan. 30, 1957 3 Sheets-Sheet l f6 BASS TREBLE DON L. BOA/HAM,

INVENTOR.

HERZ/G I JESSUP, ATTORNEYS.

Nov. 24, 1959 D. L. BQNHAM 2,913,948

; ATTENUA'I'ING CIRCUIT FOR ELECTRIC ORGAN Filed Jan. 50, 1957 3 Sheets$heet 2 124a J 122+ 122a i J16 uss I'REBLE OON L. EON/MM,

INVENTOR.

, HERZ/G a Jsssue I By ATTORNEYS. 142 g Nov. 24, 1959 V D. BONHAM 2,913,948

ATTENUATING CIRCUIT FOR ELECTRIC ORGAN Filed Jan. 30, 1957 3 Sheets-Sheet 3 vvv W fi/vv DON L. BOA/HAM,

IN VENTOR.

; HERZ/G a JESSUB 5 BY ATTORNEYS. 24.2

United States Patent ATTENUATING CIRCUIT FOR ELECTRIC ORGAN Don L. Bonham, Pacoima, Califl, assignor to Pacific Mercury Television Mfg. Corp., Sepulveda, Calif a corporation of California Application January 30, 1957, Serial No. 637,309

8 Claims. (Cl. 84--1.19)

This invention relates to an attenuating means or circuit, and particularly to an attenuating means for an electric or electronic organ.

It is an object of this invention to provide simple, inexpensive means whereby the tonal effect of a two-manual organ may be somewhat simulated by a single-manual organ.

A major advantage of a two-manual organ over a single-manual organ is the fact that treble maybe played on one-n1anual with relatively high volume while the bass is being played on the other manual at low volume, thus accentuating the treble; or this effect may be reversed by accentuating the bass rather than the treble. It is an object of this invention to provide simplified selective circuitry whereby in a single-manual organ either the bass or the treble may be accentuated, and if desired, a third position may be provided in which neither bass nor treble is accentuated, but each is accorded the same amplification of volume. In practice, this accentuation, being entirely relative, is not effected by actual amplification, but instead, is elfected by attenuating one portion of the manual or keyboard more than the other portion.

With a manual divided into two portions, as described above, and with for example, the circuit set to accentuate the treble, i.e. attenuate the bass, there would be a marked and somewhat disconcerting abrupt change in volume as one moves from bass to treble or vice-versa. In order to alleviate this abrupt change, it is an object of this invention to provide means for introducing a modulating or transition zone between treble and bass, whereinthe volume shifts gradually from the low volume to which the bass is set to the highvolume of the treble, or vice-versa,-dependingon the setting of the control.

It is a further object of this invention to provide means whereby'with a-simple three-position control knob or switch the organist may at his selection attenuate the treble, attenuate neither treble nor bass, or attenuate the bass.

In accordance'with these and other objects which will become apparent hereinafter, preferred forms of the present invention will now be described with reference to the accompanying drawings wherein:

Fig. l is a circuit diagram of a simplified form of the present invention embodying certain features thereof; Fig. 2 is a-diagram of a more refined form of the .:present invention embodying certain modulating or transiare employed to achieve various tonal effects. To the input 12 of the formant circuit 11 are applied electric signals-corresponding to all of the notes being played on the organ keyboard at any given moment. Passing through-the formant circuit '1-1,'these signals'appear on the output terminal 13 of the formant circuit, and thence to any suitable amplifier and/or loudspeaker system.

Audio signals are generated in at least two oscillators or other tone-producing means, the outputs of which are applied respectively to the terminals 16 and 17, the other terminals of the oscillators being grounded, in customary fashion. The present invention has particular applicability to that type of electric organ wherein each key of the manual (or each small group of keys, as for example, each two or three keys), has associated therewith its own discrete oscillator. The oscillators are tuned or tunable to successively increase frequencies of a musical scale, such as tempered chromatic scale, in conventional fashion. Thus, for all of the notes on the lower portion or bass end of the keyboard, there will be a plurality of oscillators 41 corresponding to individual keys or groups of keys at the bass end of the scale. The outputs of all of these oscillators 41 will be applied to the terminal 16. In similar manner, the outputs of all of the upper or treble oscillators 42 will be applied to the terminal 17.

Interposed between the terminals 16, 17 and the output circuit 11 is the selective attenuating means or circuit 18 forming the subject matter of the present invention.

Broadly, the attenuating circuit 18 comprises attenuating means, in the form of impedances or resistors 19 and 21; and multiple position switch means 22 for selectively discriminating between either the bass oscillators 41, or the treble oscillators 42, or discriminating against neither the bass nor treble and allowing both oscillator banks 41 and 42 to be applied directly to the output circuit 11 without attenuation. In one position of the switch means 22 the bass oscillators 41 are applied directly from terminal 16 are applied directly to the output circuit 11 without attenuation, While simultaneously the treble oscillators 42 connected to the terminal 17 are required to traverse at least a portion of the attenuating means 18 before being applied to the output circuit 11; this causes selective discrimination in favor of the bass oscillators. In another position (the intermediate position of the switch means 22) neither bass nor treble oscillators are attenuated, but both are applied uninhibited to the output circuit 11. In a third position of the switch means 22, the bass oscillators 41 connected to terminal 16 are attenuated by at least the portion of attenuating means 18, while the treble oscillators 42 connected to terminal 17 are applied without attenuation di rectly to the output circuit 11.

Specifically, there is illustrated in Fig. l, a switch means 22 consisting of three sections 22a, 22b, and 22s. Each of the sections has a moveable arm or pole referred to generically as 23 and three output terminals referred to generically as 24, 26 and 27, corresponding to the three positions of the switch means 22. The three poles 23a, 23b, and 230 constituting 23 are ganged together for simultaneous movement and operation.

The terminal 16, to which are connected all of the bass oscillators 41, is connected to the pole 23a of the switch section 22a. The treble terminal 17 is connected to the pole 23b of the second switch section 22b. The input terminal 12 of the circuit 11 is connected to the pole 230 of the third switch section 220. The first terminal 24a of theswitch section 22a is connected to the first terminal 240 of the switch section 22c. Thus, when the switch means 22 is in the first or left-hand position, the bass oscillators 41 connected to terminal 16 are connected directly to the output circuit 11 without attenuation.

The first terminal 24a of the switch section 22a is also connected to the left-hand terminal of the attenuating impedance or resistor 21. The right-hand terminal of the resistor21 isconnected to the first terminal 241201 the second switch section 22b. switch means 22 is in the left-hand position, all of the treble oscillators 42 connected to the terminal 17 are applied to the input of the circuit 11 through the resistor 21 and are thus attenuated.

All of the second terminals 26a, 26b and 26c of the respective three switch sections are connected together as shown. As a result, when the switch means 22 is in the second or middle position, both the terminals 16 and 17 are connected, without attenuation, to the circuit 11. Hence. in this position, neither bass nor treble is discriminated against and both sides of the manual come through with equal volume.

The third terminal 27b of the second switch section 22b is connected directly to the third terminal 270 of the third switch section 220. The third terminal 27a of the first switch section 22a is connected to the left-hand terminal of the attenuating resistor 19, while the right-hand terminal of the resistor is connected to the terminal 270. Thus when the switch means 22 is in the third or righthand position, the treble oscillators 42 are connected unimpeded to the output circuit 11 while the bass oscillators 41 connected to the terminal 16 are all attenuated by being applied to the output circuit only through the resistor 19.

Operation of the circuit of Fig. 1 will now be briefly reviewed. If th'' o r'g anist does not wish to attenuate either the bass or treble, but instead wishes to allow full volume from each to be applied to the output circuit 11, he places the switch means 22 in its intermediate position. In this position, signals from the bass oscillators 41 proceed from the terminal 16, through the pole 23a, terminal 26a, terminal 260, pole 23c, directly to the output circuit 11. In similar manner, signals from the treble oscillators 42 proceed from the terminal 17, to the pole 23b, terminal 26b, and thence join with the bass signals at the terminal 26a.

If the organist wishes to simulate a two-manual organ, as for example, by making the bass of greater volume than the treble, he moves the switch means 22 to the left-hand position. Signals from the bass oscillators 41 proceed uninhibited from the terminal 16 through the pole 23a, terminal 24a, terminal 240, pole 23c, directly to the output circuit 11. Signals from the treble oscillators 42 proceed from the terminal 17 to the pole 23b, to the terminal 24b, through a portion of the attenuating means 18, i.e. the resistor 21, and thence to the switch section 220 and output circuit 11. Thus, the organist achieves greater volume from his bass notes than for his treble notes.

If a reverse effect is desired, i.e. discrimination against the bass notes rather than the treble, the switch means 22 is placed in the right-hand position. In this case, the treble notes proceed unimpeded through the output circuit 11 while the bass notes are forced to traverse another portion of the attenuating means 18, in this case the resistor 19, before being applied to the output circuit 11.

Whenever any portion of the attenuating circuit 18 is interposed between an oscillator and the output circuit 11, there is created an imbalance of the loading on the oscillator. In certain situations, and when employing certain oscillator circuits, this imbalance may shift the oscillator frequency to such an extent as to be objectionable from a musical standpoint. To alleviate this problem, loading circuit means are provided for properly loading the respective oscillators whenever the switch means 22 is in position to interpose any portion of the attenuating means 18 between an oscillator and the output circuit 11.

In Fig. 1, this loading circuit means comprises resistors 31 and 32, the former being connected between ground and terminal 27a and the latter between ground and terminal 24b. I No loading resistor is necessary for the terminal 2411, because when the pole 23 is in the left-hand position, the bass oscillators 41, connected to the terminal 16, are connected directly to the output circuit 11 and are accorded the loading for which they were designed.

In this manner, when the 4 7 When, however, the switch means 22 is in the right-hand position, the loading effect of the output circuit 11 on the bass oscillators 41 is felt only through the attenuating resistor 19. This decrease in loading is offset by the parallel connected resistor 31, which brings the loading on the base oscillators 41 back to the value for which they were designed, and maintains their output frequency constant.

In similar vein, the loading resistor 32 brings the loading on the treble oscillators 42 back to the proper value when the switch means 22 is in the left-hand position.

When change in loading on the oscillators is not a serious problem, that is When it may be tolerated, so that the resistors 31 and 32 may be eliminated, it is possible to eliminate the third switch section 22c, and connect the three leads from the circuit 18 directly to the output circuit 11. This is possible because the operation of the other two switch sections 22a and 22b is such as to automatically isolate the output circuit 11 from all but the desired connections.

Under certain conditions of use, the circuit of Fig. 1 may be objectionable in that it has the shortcoming that when a run is played which moves from treble to bass, or vice-versa, there is an abrupt change in volume as one moves from one range to the other. In order to modulate this change, a more refined circuit, as illustrated in Fig. 2 may be employed. In employment of the Fig. 2 circuit, a transition region is provided intermediate treble and bass. That is to say, one or more oscillators 143 lying in the middle of the keyboard and having oscillation frequency or frequencies intermediate the bass and treble frequencies, form an intermediate portion which is neither treble nor bass.

To this end, the circuit of Fig. 2 is provided with three input terminals 116, and 117. In actual practice, as intimated hereinbefore, the present invention is particularly well suited for use in a monophonicpolyphonic type of organ. In this type of organ, the signals or tones for the bottom or first small group (for example three) of notes of the keyboard are supplied by a single oscillator 141'. The next three successive or consecutive notes in turn have their own oscillator 141, and so on up the entire keyboard. In this way, a polyphonic instrument is created, that is, an instrument in which many notes may be sounded simultaneously; at the same time, the number of oscillators required is only one-third of the number of keyboard keys.

This type of organ is applied to the circuit of Fig. 2 by selecting the middle or intermediate oscillator 143 for connection to the intermediate terminal 115. This is the oscillator that handles the three consecutive notes in the middle of the keyboard. All of the oscillators 141 below this constitute the bass section and are connected to the terminal 116, and all of the oscillators 142 above constitute the treble section and are connected to the terminal 117. The middle three notes supplied by the middle oscillator 143 thus constitute a transition zone between bass and treble. Obviously, if desired, this transition zone may be widened by connecting two consecutive oscillators to the terminal 115 although it is preferred to connect only one.

The attenuating circuit 118 of Fig. 2 is so arranged that the intermediate oscillator signals, from the terminal 115, are attenuated only partially while the bass or treble signals, as the case may be, are more fully attenuated. Thus, a transition zone is effected, so that when a run is made from bass to treble, with the switch or control set to accentuate in favor of the bass, the bass notes will come through loudest, the three notes in the transition zone will be softened or attenuated to a certain degree, and the treble notes will be still further softened or attenuated.

The transition zone is incorporated with the switch means 122 by adding a fourth switch section 122d to the three s9l 9ns illustrated in Fig. 1. The intermediate termina 1. is ed aected t t e rol 123 of th int rmediate switch section. The first output terminal 124d of the section 122d is connected to the junction between two resistors 121a and 121b, which together constitute pair of series connected impedances, corresponding generally to the resistor or impedance 21 of Fig. 1. In similar manner, the third terminal 127d is connected to the juncture point between the resistors 119a and 119b, which together constitute a second pair of series connected resistors, corresponding generally to the resistor 19 of Fig. 1.

The attenuating circuit of Fig. 2 operates as follows. When the organist desires to discriminate in favor of the bass portion of the manual, he moves the switch means 122 to the left-hand position. This operates each of the four ganged poles 123 to the respective left-hand positions. The bass oscillators 141 are then connected directly to the output circuit 111 through the pole 123a and terminal 124a. The intermediate oscillator 143, connected to the terminal 115, is connected through the pole 123d and resistor 121a to the terminal 124a. Signals from the intermediate oscillator 143 are thus somewhat attenuated by virtue of the energy absorbed in resistor 121a. Signals from the treble oscillators 142, connected to the terminal 117, must traverse both the resistor 12112 and the resistor 121a and are thus attenuated to the greatest extent. Hence, as the organist passes from bass to treble, a transition zone of volume change is effected by virtue of the intermediate attenuation applied to the intermediate three notes of the keyboard.

When the switch means 122 is in its middle position, each of the three terminals 116, 115 and 117 is applied directly to the output circuit 111 and there is no attenuation.

When the organist wishes to discriminate in favor of the treble, he moves the switch means 122 to the righthand position. Signals from the terminal 117 proceed unimpeded to the output circuit 111. Signals from the intermediate terminal 115 are somewhat attenuated by passing through the resistor 11%. Signals from the bass terminal 116 are attenuated the most by being forced to traverse the series connected resistors 119a and 119]). Thus, whether the organist discriminates in favor of the bass or treble, there is a transition or modulating zone between the bass and treble portions of the manual which eflects a modulation of volume differential as the organist plays.

As in the case of Fig. 1, the insertion of any portion of the attenuating impedance means 118 between the oscillators 141, 143, 142 and the output circuit 111 creates an imbalance on the loading of the oscillators, and it is desirable whenever the switch means 122 is in such positions to properly load the oscillators by the loading resistors 151.

Likewise, as in the case of Fig. 1, if the problem of improper loading of the oscillators is not a serious one, not only may the loading resistors 151 be eliminated, but the switch section 122a may be also eliminated, and the three leads may be connected directly to the input terminal 112 of the output circuit 111.

If desired, the second or intermediate terminals of the switch means 122, i.e. the terminals 126, may be eliminated, thus changing the switch means into a twoposition, rather than a three-position switch. This, of course, results in a discrimination either in favor of bass or in favor of treble, without any position where there is no discrimination.

In Fig. 3 there is shown a straightforward extension of the Fig. 2 circuit to include a second transitory zone in the form of another intermediate terminal 220. In the use of the Fig. 3 circuit, the keyboard is divided into .a bass section 241 and a treble section 242 as before, but two intermediate zones I, and I are provided. The first intermediate zone is constituted by the first oscillator 243 above the bass group of oscillators 241; the

second intermediate zone is constituted by the second oscillatorup 244; and the remaining oscillators 242 of the scale constitute the treble zone. It will be readily evident from the circuit of Fig. 3 that the modulating or transition zone from bass to treble is now made up of two transition steps, rather than one step, as in the case of Fig. 1. That is to say, there are four levels of sound volume encountered as one goes from bass to treble in the Fig. 3 circuit, whereas there are only three levels of sound volume with the Fig. 2 circuit.

The circuit of Fig. 3 requires an additional ganged section in the switch means 222, and an additional two attenuating resistors added respectively in series with the resistors of Fig. 2.

While the instant invention has been shown and described herein in what is conceived to be the most practical and preferred embodiments, it is recognized that departures may be made therefrom within the scope of the invention, which is therefore not to be limited to the details disclosed herein, but is to be accorded the full scope of the claims.

What is claimed is: 4

1. In an electric organ having at least three tone-producing means and an output circuit, the combination of an attenuating circuit applied between said tone-producing means and said output circuit and comprising: attenuating means, and applying means for selectively: (1) applying a certain portion of said attenuating means between one of said tone-producing means and said output circuit while simultaneously applying a lesser portion of said attenuating means between a second of said tone-producing means and said output circuit, or (2) applying a certain portion of said attenuating means between a third of said tone-producing means and said output circuit while simultaneously applying a lesser portion of said attenuating means between said second of said tone-producing means and said output circuit; said applying means comprising: switch means having at least two positions and at least four poles, each of said four poles having associated therewith at least two terminals, each of said poles being engageable selectively with one or the other of its respective terminals, three of said poles being connected respectively to said three tone-producing means, the fourth pole being connected to said output circuit, first circuit means for connecting one of said three poles to said fourth pole, the second of said three poles to said fourth pole through a portion of said attenuating means and the third of said three poles to said fourth pole through a portion of said attenuating means greater than said first mentioned portion, when said switch means is in one position, said first circuit means comprising means for connecting the first terminal of said first pole with the first terminal of said fourth pole, means for connecting the first terminal of said second pole with the first terminal of said fourth pole through said first-mentioned portion of said attenuating means, and means for connecting the first terminal of said third pole with the first terminal of said fourth pole through said second mentioned portion of said attenuating means; and second circuit means for connecting said third of said three poles to said fourth pole, said second of said three poles to said fourth pole through a portion of said attenuating means, and the first of said three poles to said fourth pole through a portion of said attenuating means greater than said last-mentioned portion when said switch means is in another position, said second circuit means comprising means for connecting the second terminal of said third pole to the second terminal of said fourth pole, circuit means for connecting the second terminal of said second pole to said second terminal of said fourth pole through said third-mentioned portion of said attenuating means, and circuit means for connecting said second terminal of said first pole to said second terminal of said fourth pole through said fourth-mentioned portion of said attenuating means.

2. The combination of claim 1 including in addition: a first loading impedance connected to said first terminal of said second pole, a second loading impedance connected to said first terminal of said third pole, a third loading impedance connected to said second terminal of said first pole, and a fourth loading impedance connected to said second terminal of said second pole.

3. In an electric organ having at least three tone producing means and an output circuit, the combination of an attenuating circuit interposed between said tone producing means and said output circuit, and comprising: a first pair of series-connected attenuating impedances, a second pair of series-connected attenuating impedances, and switch means having at least four sections, each of said sections having at least two positions of operation and including means for ganging the operation of said four sections; each of said sections having at least two output terminals; circuit means for connecting said three tone producing means to a respective three of said sections; circuit means for connecting said output circuit to the fourth of said sections; circuit means for connecting one terminal of one of said sections to a corresponding one terminal of said fourth section and to one terminal of said second pair of impedances; circuit means for connecting another terminal of said one section to one terminal of said first pair of impedances; circuit means for connecting one terminal of a second of said sections to the connection point between said second pair of impedances; circuit means for connecting another terminal of said second section to the connection point between said first pair of impedances; circuit means for connecting one terminal of said third section to the other terminal of said second pair of impedances; and circuit means for connecting another terminal of said third section to the corresponding other terminal of said fourth section and to the other terminal of said first pair of impedances.

4. The combination claimed in claim 3, including in addition: first loading impedance means connected to said other terminal of said one section, second loading impedance means connected to said other terminal of said second section, third loading impedance means connected to said one terminal of said second section, and fourth loading impedance means connected to said one terminal of said third section, for loading said tone pro- 8 ducing means when not connected directly to said output circuit.

5. The combination of claim 3 including in addition respective third terminals for each of said sections, each of said sections thus having a third position; and circuit means for connecting together the respective said third terminals.

6. In an electric organ having at least two tone-producing means and an output circuit, the combination of a multi-channel attenuating circuit between said toneproducing means and said output circuit, said attenuating circuit comprising attenuating means in at least two of said channels, and a three-position switch for selectively connecting, in two of the positions thereof, selected ones of said tone-producing means to said output circuit through respective channels having attenuating means therein and for connecting the other toneproducing means directly to said output circuit, said switch being arranged, when in a third position, to connect all of said tone-producing means directly to said output circuit.

7. An electric organ as defined in claim 6, wherein said switch comprises ganged sections, there being at least a section for each of said tone-producing means for switching the output thereof.

8. An electric organ as defined in claim 6 including load-balancing means in each of said channels having said attenuating means therein, whereby to balance the loads on said tone-producing means when the output of any one thereof is being attenuated.

References Cited in the file of this patent UNITED STATES PATENTS 1,916,187 Read June 27, 1933 1,929,032 Miessner Oct. 3, 1933 2,113,332 Morse et a1. Apr. 5, 1938 2,173,222 Belar Sept. 19, 1939 2,300,609 Zuck Nov. 3, 1942 2,585,357 Wayne Feb. 12, 1952 OTHER REFERENCES Radio Electronics Publication, vol. 23, December 1951, issue 3, pages 27, 29, 56, and 58. 

